Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

The Achilles tendon is attached to the rear of the foot as shown in ( Figure 1 )

ID: 1284870 • Letter: T

Question

The Achilles tendon is attached to the rear of the foot as shown in (Figure 1) . A person elevates himself just barely off the floor on the "ball of one foot." Assume the person has a mass of 75kg and D is twice as long as d.

B.) Find the (downward) force FB exerted by the lower leg bone on the foot.

Express your answer to two significant figures and include the appropriate units.

CommentFigure 12-63

The Achilles tendon is attached to the rear of the foot as shown in (Figure 1) . A person elevates himself just barely off the floor on the ball of one foot. Assume the person has a mass of 75kg and D is twice as long as d. B.) Find the (downward) force FB exerted by the lower leg bone on the foot. Express your answer to two significant figures and include the appropriate units. CommentFigure 12-63

Explanation / Answer

Normal reaction at "ball of one foot." must balance the person's weight

N = mg = 75 * 9.8 = 735 N

Ft + N = Fb   - >1

consider moments balance about "ball of one foot"

Fb*D = Ft* (D+d)

Fb = 3Ft  

Ft = Fb/3     -> 2

substitute 2 in 1

N = 2Fb/3

Fb = 1102.5 N